David Hughes is the Daily Telegraph's chief leader writer. He has been covering British politics for 30 years.

Who exactly is the mug, Mr Cameron?

Was Speaker Bercow taking a nap? That’s the only explanation I can think of for his failure to upbraid David Cameron for subjecting Ed Miliband to low – and I suspect unparliamentary –abuse during PM’s Questions. The Prime Minister described the Labour leader as “a complete mug”. There are many who might agree with that assessment, some of them sitting behind Mr Miliband on the Labour benches. But that’s not the point. The Chamber of the House of Commons is supposed to be about the cut and thrust of ideas, not the swapping of playground insults. Once again Cameron was in Flashman mode, and it’s not a good look. I assume he resorted to the abuse because he’s feeling badly rattled after Monday’s clobbering by his own MPs in the referendum vote. He knows he handled that badly but to follow it up with a display of petulance at the dispatch box is counterproductive.